The objective of the studies described in this proposal is to provide core virology laboratory support for AIDS Clinical Trials Group (ACTG) studies conducted by the University of Rochester AIDS Clinical Trials Unit (ACTU). It is understood that a Virology Core Laboratory would have he responsibility to conduct virologic studies for other ACTUs as well. The specific aims of this project include: 1) performing virologic studies to measure antiretroviral effects among patients enrolled in ACTG clinical trials, 2) to store patient samples and maintain an efficient inventory system, and 3) to develop, evaluate and incorporate new techniques for measurement of virologic markers of HIV infection and disease. Techniques which are proposed for use in these studies include qualitative peripheral blood mononuclear leukocyte (PBML) cultures and measurement of p24 antigen. The applicants are certified by the ACTG's Viral Reference Laboratory (VRL) and currently perform in excess of the required 500 HIV cultures and 2,600 p24 antigen determinations per year. Additional techniques which will be employed to measure antiretroviral effects include quantitative PBML cultures, qualitative and quantitative plasma cultures, and measurement of HIV proviral DNA and virion RNA using the polymerase chain reaction (PCR). All of these techniques are established at the University of Rochester ACTU. Although not requested in the RFA, the University of Rochester ACTU is also prepared to measure HIV susceptibility to antiretroviral drugs, and, if necessary, to conduct laboratory investigations of other virus infections which commonly occur in patients who are infected with HIV.